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Full text of "Alaskan glacier studies of the National Geographic Society in the Yakutat Bay, Prince William Sound and lower Copper River regions"

126                                 ALASKAN GLACEER STUDIES
The great volume of water involved in this work of destruction is clearly shown now by the network of small and large channel scars which extend across the formerly alder-covered part of the fan as well as by the score or two of streams which had to be forded in crossing the alluvial fan in 1906.
Banded Moraines Outside the Interior Flat in 1909. In general features the outer banded moraines of the Variegated Glacier bulb beyond the interior flat were in the same condition as in 1905. It is certain that the thrust from the advance of the Variegated Glacier did not affect this stagnant portion of its bulb in the least. In our excursions over it several observations in addition to those of previous years were made. Perhaps the most important of these was the clear indication of the presence of ice under even the outermost portion of the western edge, nearest Hubbard Glacier, and only a few hundred feet from the sea. While ice was not actually seen here, there was a small pond of cold water milky with sediment, such as could only come from ice, and on its shores were areas of fresh slumping clearly indicative of the presence of ice beneath.
Farther back from the fiord there was increasing evidence of the presence of ice,both in the amount of slumping and in the condition of the vegetation. Over most of the black hornblende moraine there were abundant small areas with no vegetation whatsoever. Then came little clusters of flowering plants, or equisetae, or grass, or willows from one to five years old; and now and then a large willow bush or even a cluster of them.
Marginal Drainage. The drainage condition is noteworthy. The northern marginal drainage followed the ice edge for a while, then cut across a part of the glacier in a narrow ice valley, then expanded over a broad interior flat, which rested on glacier ice and was completely bordered by ice except in the two gorges, one at the point where the drainage entered it, the other at the point where it left the interior flat. On this flat the stream was depositing much of its sediment; it then emerged from the interior flat through a gorge cut across the outer bulb of the glacier, and finally entered the sea over the large, partly alder-covered alluvial fan. In 1905 a still larger stream and perhaps practically the whole drainage of the Variegated Glacier and of Orange Glacier entered this flat and joined the north stream just above the outlet gorge. It is a most exceptional drainage condition, and the deposits left here when the ice melts out from beneath them will be complex and peculiar. There were no visible changes in drainage or moraine distribution by June, 1910, though time was not available for a re-examination that year.
General Description. Immediately east of Variegated Glacier is a broad valley occupied by a glacier somewhat more than a mile in width, which terminates close by the southern margin of Variegated Glacier in a low, gently-sloping ice front which on the northern side barely coalesces with the Variegated Glacier. From this front the Orange Glacier rises with moderate slope, varying from 5 to 15 degrees, though rarely attaining so steep a slope as the latter, finally reaching a broad, flat divide at an elevation of about 2500 feet. The divide area is above the snow line and from it the ice descends not only westward to form the Orange Glacier, but eastward towards Nunatak Fiord to form an unnamed glacier, to which reference will be made in the next section. The valley that this glacier occupies is therefore a through valley, and the glacier is a typical, though small example, of a through glacier.
The Orange Glacier surface is smooth and relatively free from crevassing, the few